1. Field of the Invention
The present invention relates to an image forming apparatus, a sensing method, and a recording medium, and more particularly, to an image forming apparatus including a moving body, a sensing method using a sensor that receives light reflected from an object, and a computer-readable recording medium storing therein a program used in an apparatus equipped with a sensor that receives light reflected from an object.
2. Description of the Related Art
An image forming apparatus typically includes a photosensitive drum and a charging device, an exposure device, and a developing device, etc. which are arranged around the photosensitive drum. The surface of the photosensitive drum is uniformly charged by the charging device, and the charged portion is exposed to a laser light emitted from the exposure device. As a result, an electrostatic latent image is formed on the photosensitive drum, and this electrostatic latent image is developed into a toner image by the developing device.
The toner image on the photosensitive drum is transferred onto a sheet conveyed on a conveyance belt. The sheet onto which the toner image has been transferred is detached from the conveyance belt, and is conveyed to a fixing device, and then after toner is fixed on the sheet by the fixing device, the sheet is discharged from the image forming apparatus.
The fixing device includes a fixing belt for applying heat and pressure to a sheet. For example, in an image forming apparatus available for A4 and A3-size sheets, when the fixing is repeatedly performed on A4-size sheets fed in portrait orientation, longitudinal streak-like abrasions may occur on portions of the surface of the fixing belt corresponding to the positions where the both ends of the A4-size sheets in a sheet width direction have passed. This is because the surface of the fixing belt is roughened by burrs at the edges of the sheets and paper dust.
At this time, when an A4-size sheet in landscape orientation or an A3-size sheet in portrait orientation is fed, so-called gloss streaks corresponding to the longitudinal streak-like abrasions appear on the surface of an image formed on the sheet, and the image quality is deteriorated. Consequently, an image forming apparatus capable of detecting a surface condition of a fixing member has been invented (for example, see Japanese Patent Application Laid-open No. 05-113739 and Japanese Patent No. 4632820).
Demands for the image quality on image forming apparatuses are increasing every year. However, image forming apparatuses disclosed in Japanese Patent Application Laid-open No. 05-113739 and Japanese Patent No. 4632820 have difficulty in stably detecting a surface condition of a fixing member with high accuracy, and may cause deterioration in the image quality.